/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.nutch.protocol.httpclient;

// JDK imports
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;

// Slf4j Logging imports
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// Hadoop imports
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configurable;

// Nutch imports
import org.apache.nutch.metadata.Metadata;


/**
 * Provides the Http protocol implementation
 * with the ability to authenticate when prompted.  The goal is to provide 
 * multiple authentication types but for now just the {@link HttpBasicAuthentication} authentication 
 * type is provided.
 * 
 * @see HttpBasicAuthentication
 * @see Http
 * @see HttpResponse
 * 
 * @author Matt Tencati
 */
public class HttpAuthenticationFactory implements Configurable {

    /** 
     * The HTTP Authentication (WWW-Authenticate) header which is returned 
     * by a webserver requiring authentication.
     */
    public static final String WWW_AUTHENTICATE = "WWW-Authenticate";
	
    public static final Logger LOG = LoggerFactory.getLogger(HttpAuthenticationFactory.class);

    private static Map auths = new TreeMap(); 

    private Configuration conf = null;
    
    
    public HttpAuthenticationFactory(Configuration conf) {
      setConf(conf);
    }

   
    /* ---------------------------------- *
     * <implementation:Configurable> *
     * ---------------------------------- */

    public void setConf(Configuration conf) {
      this.conf = conf;
      //if (conf.getBoolean("http.auth.verbose", false)) {
      //  LOG.setLevel(Level.FINE);
      //} else {
      //  LOG.setLevel(Level.WARNING);
      //}
    }

    public Configuration getConf() {
      return conf;
    }
 
    /* ---------------------------------- *
     * <implementation:Configurable> *
     * ---------------------------------- */


    public HttpAuthentication findAuthentication(Metadata header) {

        if (header == null) return null;
        
    	try {
			Collection challenge = null;
			if (header instanceof Metadata) {
				Object o = header.get(WWW_AUTHENTICATE);
				if (o instanceof Collection) {
					challenge = (Collection) o;
				} else {
					challenge = new ArrayList();
					challenge.add(o.toString());
				}
			} else {
				String challengeString = header.get(WWW_AUTHENTICATE); 
				if (challengeString != null) {
					challenge = new ArrayList();
					challenge.add(challengeString);
				}
			}
			if (challenge == null) {
                                if (LOG.isTraceEnabled()) {
				  LOG.trace("Authentication challenge is null");
                                }
				return null;
			}
			
			Iterator i = challenge.iterator();
			HttpAuthentication auth = null;
			while (i.hasNext() && auth == null) {
				String challengeString = (String)i.next();
				if (challengeString.equals("NTLM")) {
				   challengeString="Basic realm=techweb";
		                  }
		               
                                if (LOG.isTraceEnabled()) {  
		                  LOG.trace("Checking challengeString=" + challengeString);
                                }
				auth = HttpBasicAuthentication.getAuthentication(challengeString, conf);
				if (auth != null) return auth;
				
				//TODO Add additional Authentication lookups here
			}
		} catch (Exception e) {
			LOG.error("Error: ", e);
		}
        return null;
    }
}
